Core Data migration failing with error: Failed to save new store after first pass of migration - iphone

Question

In the past I had already implemented successfully automatic migration from version 1 of my data model to version 2. Now, using SDK 3.1.3, migrating from version 2 to version 3 fails with the following error:
Unresolved error Error Domain=NSCocoaErrorDomain Code=134110 UserInfo=0x5363360 "Operation could not be completed. (Cocoa error 134110.)", {
NSUnderlyingError = Error Domain=NSCocoaErrorDomain Code=256 UserInfo=0x53622b0 "Operation could not be completed. (Cocoa error 256.)";
reason = "Failed to save new store after first pass of migration.";
}
I have tried automatic migration using NSMigratePersistentStoresAutomaticallyOption and NSInferMappingModelAutomaticallyOption and also migration using only NSMigratePersistentStoresAutomaticallyOption, providing a mapping model from v2 to v3.
I see the above error logged, and no object is available in the application. However, if I quit the application and reopen it, everything is in place and working.
The Core Data methods I am using are the following ones
- (NSManagedObjectModel *)managedObjectModel {
if (managedObjectModel != nil) {
return managedObjectModel;
}
NSString *path = [[NSBundle mainBundle] pathForResource:#"MYAPP" ofType:#"momd"];
NSURL *momURL = [NSURL fileURLWithPath:path];
managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:momURL];
return managedObjectModel;
}
- (NSManagedObjectContext *) managedObjectContext {
if (managedObjectContext != nil) {
return managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
managedObjectContext = [[NSManagedObjectContext alloc] init];
[managedObjectContext setPersistentStoreCoordinator: coordinator];
}
return managedObjectContext;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
if (persistentStoreCoordinator != nil) {
return persistentStoreCoordinator;
}
NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: #"MYAPP.sqlite"]];
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
[NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
NSError *error = nil;
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];
if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:options error:&error]) {
// Handle error
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
}
return persistentStoreCoordinator;
}
In the simulator, I see that this generates a MYAPP~.sqlite files and a MYAPP.sqlite file. I tried to remove the MYAPP~.sqlite file, but
BOOL oldExists = [[NSFileManager defaultManager] fileExistsAtPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: #"MYAPP~.sqlite"]];
always returns NO. Any clue? Am I doing something wrong?
Thank you in advance.

Answer 1

I ran into this as well and after reading as much Apple docs and web postings as I could find there didn't seem to be an answer. In my case the manual migration was working as well but when I went to open up a new coordinator it would give the same error you had. I finally decided to go back to my last working version of the data model and do a series of small changes/versions and see where it broke the auto-migration capabilities to drill further into it and it turned out it didn't. Now I can add entities, attributes and relationships without issue and they auto-migrate. Any chance you deleted an interim version of the datamodel?

Answer 2

For what it's worth, the Magical Record Core Data utility package includes this hack:
[coordinator MR_addAutoMigratingSqliteStoreNamed:storeFileName];
//HACK: lame solution to fix automigration error "Migration failed after first pass"
if ([[coordinator persistentStores] count] == 0)
{
[coordinator performSelector:#selector(MR_addAutoMigratingSqliteStoreNamed:) withObject:storeFileName afterDelay:0.5];
}
You might try something similar. I have been unable to find an explanation of what the problem is, though, or why just retrying it would work.